Acadia Shares Sink on Failed Study

Acadia Pharmaceuticals (ACAD Quote) disclosed Monday that a midstage trial for schizophrenia drug ACP-104 didn't meet its primary or secondary endpoints.

Acadia's stock nearly halved, falling $4.15, or 49%, to open trading at $4.34.

The San Diego-based biopharmaceutical company said the phase IIb trial looked at two doses of the drug, neither of which were more effective than the placebo. "While we will thoroughly analyze the data to understand the outcome, we currently do not anticipate conducting further studies with ACP-104," said CEO Uli Hacksell in a company statement.

The company's mid-to-late stage pipeline also includes its lead product, pimavanserin, which is being studied as a co-therapy for schizophrenia in phase II trials and as a treatment for Parkinson's disease psychosis in phase III trials.

Investors and analysts have been waiting for word on a possible partnership for pimavanserin. "We continue to expect ACADIA will enter into a partnership for pimavanserin, however concede that the delay is causing us to question our expectations for the deal terms," wrote Piper Jaffray analyst Edward Tentoff in a note on May 6 -- prior to today's ACP-104 data.

The stock has traded as high as $17.33 in the last year, but has closed under $10 since March -- at $8.49 on Friday. The stock was down $3.74, or 44.1%, at $4.75 in recent trading Monday, well off its 52-week low of $7.63.